Boat raising and lowering gear



April 19, 1932. L. A. DIXON ET AL 1,855,013

BOAT RAISING AND LOWERING GEAR Filed Feb. 8, 1930 4 Sheets-Sheet 1 April19, 1932. L. A. DIXON ET AL 7 1,855,013

BOAT RAISING AND LOWERING GEAR Filed Feb. 8, 1930 4 Sheets-Sheet 2 April19, 1932. L. A. DIXON ET AL 1,855,013

BOAT RAISING AND LOWERING GEAR- Filed Feb. 8, 1930 4 Sheets-Sheet 3 Aril 19, 1932. 1.. A. DIXON ET AL 1,855,013

BOAT RAISING AND LOWERING GEAR Filed Feb. 8, 1930 4 Sheets-Sheet 4Patented Apr. 19, 1932 yej-m'ren STA TBS BATENT: olnuca 29.4.53. BAIINGK411 9 51 3 1313 Application filed Eebruary 8,, Serial No. {26,843, andin Great BritainMay 3,1929.

This invention. is for improvements in orrelating to raising andlowering gear for ships" boats, I which gear isv of the type, comprisingdavi-t arms constructed to move outhoard automaticallyunder the weightof the boat when they are released; Such davits maybe controlled eitherby the falls for the boat, or by separate ropes or cables, and oneobject of} the invention is to improve the coniii struction of gearofthis type with a view to obtaininga more efl'icient application of thewer required to house the davit-arms and the boat.

The invention accordingly comprises a 5: boat-raising and lowering geart the type described wherein the davit-arm carries a movablefulcr-um'arranged to travel in one path (for example, a path inclineddown wardly and outwardly-"to the side of the 55 ship), and the lowerendof the dav-it-ar-m is constrained to move in another dissimilar pathsaid paths being so arranged as to cause a simultaneous lowering andoutboard turning movement of the head of the davitarm; when thedavit-a-rm is released.

According toanotherf eature-of this invention, the path aforesaid of thelower end of 'the davit-arm slopes downwardly and outwardlyfrom theinner end, and; is thereafter curved inwardly from the side of the shipto terminate in a substantially horizontal portion. This shaping givesanautomatic lock which holds the davit-arm in its out- I turned positionagainst accidental inboard movement.

According to. a further feature. of the invention, a multiple purchase.system 01. puley t ck e is pr vi ed for ont li g mit-a m m beccatr ledrespectiv y y two indepen, ent systemsof pulleys and a .kle, e n t n e Qfi ren Pu lierr m re omplet un rsta d ng of t invention, fourembodiments thereof will new be desc bed. by Waycf. xamp e t Gi-QIQQ Qt9 the aqq mpany drawi S. which are ota d agrammatic character. n

the drawings, .Figure his a side elevation 011 one construction, and

. Figures-2, 3 and 4: are similar views of separate-modifications.

Like reference numerals indicate like parts in thevarious figures of thedrawings.

i In the. construction shown in Figure 1, there is provided adavit-stand10 comprisingtwo track-members 11 which are spaced apart in.plan Each of these track-members has a horizontal portion 12 situatedabove the deck ot-the ship and supported bystandards 13 or secured tothe engine. casing. or other. structure as may be convenient Thishorizontal portion merges into an inclined portion. 14; which slopesdownwardly and outwardly to the side of the ship, and termi nates in asubstantially verticalportion 15 which is fixed at its lower end to thedeck of the ship. 7

A davit-arm 16 is mounted between the two track-members 11 whichdavit-arm is curved outwardly at its upper end towards the side of theship and has at its lower end a substantially straight portion. Near theinner end of said straight portion the davitarm is provided with amovable tulcrum or main bearing in the form of rollers 17- ar-' rangedoneon each side ofthe davit-arm, and to run on the inclined portion 14ofthe trackmembers. The lower end of the davit-arm has a rearwardlyextending projection on which two rollers 18' are mounted. The saidrollers are received and adapted to travel in a curved track 19 providedon plates or brackets 20 on the davit-stand 10. The track 19 is shapedso as to provide a straight or substantially straight, portion 21 whichis inclined down-1 ward-Ly at a small angle to the inclined por tion 1 4of the track-members 1'1. Thisin clined portion of the track 19 slopesoutwardlytowar-dsthe side of the ship and is thereafter curved inwardlyas shown at 22 and finally terminates in a substantially hori- 1zontalportion 23. This shapingof the lower: end of the track 19-gives anautomatic locking which holds the davit-arminits outboardpositi onagainst accidental inboard movement; Theboat and the davit-arm are bothcntrolled by a single cable 24'which is led from 1 a winch or otherhoisting apparatusKnot shown). over apulley-25 carried by a bracket 1 26on the davit-stand 10. The cable extends thence substantially in thedirection of the inclined portion 14 of the track-members 11 and arounda pulley 27 on the davit arm 16, a

which pulley may be adjustably mounted on the davit-arm. V

From the pulley 27 the cable is led backwardly in a direction parallel,or substantially so, to the run of the cable between the pulleys 25 and27. The'cable is then led around a pulley 28 on the upper end of thebracket .26 and thence to a pulley 29 on the head of the davit-arm. Thecable 24 then passes round a movable pulley 301mm which the boat 31(indicated in chain lines) is suspended by any convenient means; The endof the cable is secured to the head of the davit-arm.

Any suitable locking device can be provided for holding the davit-arm inthe housed or inboard position.

When the cable 24 is released, the rollers 17 constituting the movablefulcrum of the davit-arm, traveldownthe inclined portion 14 of thetrack-members 11 and during this movement the rollers'18 on the lowerend of the davit-arm travel in the curved track 19. Thus a simultaneouslowering and outboard turning movement of the boatis effected until therollers 18 reach the end of the track 19. The davit-arm then comes torest against a stop on the davit-stand. Any convenient davit-stop may beprovided; in the constructions shown on the drawings this stop takes theform of abatten 48 between the track-members 11. It will be appreciatedthat when the rollers 18 reach the end 23 of the track 19, a furtherslackening of the cable effects the lowering of the boat until it iswater-borne. In this positionthe davit-arm is locked by the curved track19 and the rollers are prevented from running backwardly up the inclinedtrack 14 until a force is appliedatthe head of the davit-arm. When apull is exerted on the cable 24 the boat-1s firstraised from the'wateruntil it is supported in known manner on the head of the davit-arm andthen a continued pull on the cable will cause the davit-arm to be raisedand turned inboard.

It will be appreciated that the arrangement of pulleys and tackledescribed gives adouble purchase for raising the boat, and

that when the boat is supported by the davitarm the double purchase istransferred to the arm for hauling it inboard. If desired, the pulley 30may bedispensed with and the end of cable 24 be connected directlyto theboat.

- Moreover, it will be seen that the force exert ed ;when the davit-armis moving inboard or outboard acts substantially in the direction oftravel of the movable .fulcrum, and the force controlling thet'urning ofthe davitarm acts as; a moment about themovable fulcrum. I Also thatthere isinotat any time during the travel of the davit-arm any verticalforce exerted on the rollers constituting the movable fulcrum.

The embodiment of the invention shown in Figure 2 is very similar tothat illustrated in Figure 1. The cable 24'instead of passing in Figures1 and 2 isstraight,.but isinclined downwardly and inwardly relatively tothe side of the ship. The boat 31 can be raised or lowered by a, cable35 which .is ledfrom a winch. or other hoisting mechanism (not:

shown) around a pulley 36 onthe davit-arm 16,'and thence to a sixefallpulley block system 37 whereof-the upper or fixed block is secured tothe head of the davit-arm and the lower or movable block is connected tothe boat 31. The end of the cable 35 is fixed at 38 to the head of thedavit-arm.

The davit-arm is controlled bya separate system of pulleys and tacklecomprising a' cable 39 which is led from any suitable winch or otherhoisting mechanism (not shown).

The cable 39 passes first around a pulley 40 in a direction"approximately parallel to the inclined por-- on the davit-stand 10,thence tion 14 of the track-members 11 andaround a pulley 41 mounted onthe davit-arm 16 coaxially with the rollers 17 ley 41 the cable 39 isled. backwardly in a direction parallel to the runof the cable betweenthe pulleys 40 and 41. The cable then passes around a pulley 42 onthelda'vit-stand,

coaxial with the pulley36, and the end. of the cable is secured at '44to'the davitstand. It will be observed in this. construction the boat israised by a six-fall pulley block system and the davit-arm system. 1 Y

In the construction shownin Figure 4'the boat is raised by a six-fallpulley system as A cable 45 and six-fall pulleyblock system 46 isprovided for controlling the 'd'avit-Q arm. The fixed block of"thisfsystem is mounted on the bracket 26 and the movable block isconnectedby a strop 47 to the davitv q f; .125 I It is tobe'understoodthat the invention is:

arm.

- From the pulis controlled by a purchase 115 1n the embodimentillustrated in Figure 3.

, thence around a pulley 43 on the davit arm not restricted totheconstructional details described as'any convenient arrangement ofpulleys and tackle can be employed without departing from the invention..1

We claim 1. In a boat raising and lowering gear of the type set forthwherein the davit-arms, on being released, move outboard automaticallydue to the weight of the boat, the combination with a davit-arm, onepart of which carries a movable fulcrum arranged to travel in one path,of a roller carried by another part of the davit-arm and a track whichis dissimilar to said path and on which said roller is arranged totravel, which track is so shaped that the vertical component of themovement of said roller is greater than the horizontal component atleast during the major portion of the outboard movement of the boat.

2. In a boat raising and lowering gear. of the gravity type wherein thedavit-arms move outboard automatically under the weight of the boat whenthey are released, the combination with a davit-arm which carriesintermediate of its ends a movable fulcrum arranged'to travel in a pathwhich is inclined downwardly and outwardly to the side of the ship, ofmeans to constrain the lower end of r the davit-arm to travel in a pathwhich slopes downwardly and outwardly from its inner end and isthereafter curved inwardly from the side of the ship to terminate in asubstantially horizontal portion, for the purpose set forth.

3. In a boat raising and lowering gear of the gravity type wherein thedavit-arms move outboard automatically under the weight of the boat whenthey are released and wherein one part of each daVit-arm carries amovable fulcrum arranged to travel in one path and another part of thedavit-arm is constrained to move in a dissimilar path, the combinationwith a davit-stand, of tackle for controlling the davit-arms, whichtackle includes two pulleys arranged one above the other on thedavit-stand, a pulley on one davit-arm intermediate of its ends, apulley at the head of that davit-arm, a double-purchase lifting block,and a rope which passes over the lower pulley on the davit-stand, thencearound the pulley on the davit-arm which is situated between theextremities of that arm, thence around the upper pulley on thedavit-stand and thence around the pulley at the head of the davit-armand the lifting block and is finally anchored on the head of thedavit-arm.

4. A boat-raising and -lowering gear of the type described, comprising adavit-arm which carries a movable fulcrum adapted to travel on adownwardly and outwardly extending track, a track extending downwardlyand, for at least a portion of its length, inwardly for constraining thelower end of the davit-arm, said tracks being so arranged as to cause asimultaneous lowering and outboard turning movement of the head of thedavit-arm when the davit-arm is released, and a single system of pulleysand tackle for controlling both the boat and the davit-arin so arrangedthat the boat is raised by double purchase and subsequently thedavit-arm is moved inboard by multiple purchase.

5. A boat-raising and -lowering gear of the type described,'comprisingadavit-arm which carries a movable fuicrum adapted to travel "on adownwardly and outwardly extending'tr'a'ck, a track extending downward-7 1y, outwardly and having an inward bend i,

for. constraining thelower end of the davitarm to move in an angularpath, said tracks being so arranged as to cause a simultaneous loweringand outboard turning movement of the head of the davit-arm when thedavitarm is released, and a system of pulleys and tackle for controllingthe boat and thedavit arm respectively. a r

'6. A boat-raising and-lowering gear of the type described, comprising adavit arm which carries a movable fulcrum arranged to travel anoutwardly inclined track, an inwardly inclined track constraining thelower end of the davit-arnnsaid tracks being so arranged as to cause asimultaneous lowering and outboard turning movement of the head of thedavit-arm when the davit-arm is released, and two independentsystems ofpulleys and tackle of different purchase for controlling the boat andthe davit-arm respectively. V

7. A boat-raising and -lowering gear of the type described, comprising adavit-arm which carries a movable fulcrum arranged to travel down asloping track, a track having at least a portion thereof slopinginwardly constraining the lower end of the davit-arm, said tracks beingso arranged as to cause a simultaneous lowering and outboard turningmovement of the head of the davit-arm when the .davit-arm is released, asix-fall pulley-block system for raising the boat, and a quadruplesystem of pulleys and tackle for controlling the davit-arm.

8. A boat-raising and -lowering gear of the type described, comprising adavit-arm which carries a movable fulcrum arrangedto travel down anoutwardly inclined track, an inwardly inclined track for guiding thelower end of the davit-arm downwardly, said tracks being so arranged asto cause a simultaneous lowering and outboard turning movement of thehead of the davit-arm when the davit-arm is released, and two six-fallpulley-block systems for raising the boat and controlling the davit-armrespectively.

9. In a boat-raising and lowering gear of the type described, thecombination of a davit-arm, a roller which constitutes a movable fulcrumjournalled in the davit-arm and arranged to travel on a downwardly andoutwardly extending track, a downwardly and inwardly extending trackguiding the lower end of the davit-arm, said tracks being so arranged asto cause a simultaneous lowering its and outboard turning movementof thehead of the davit-arm when the davit-arm is re-' leased, and a multiplepurchase system of pulleys and tackle for controlling the davitarm.

10. In a boat launching and stowing apparatus, a davit-arm havingrollers journalled therein adjacent its central portion and lower end,an outwardly inclined track for the former and a track having at least aportionthereof inclined inwardly for guiding the latter, which tracksare arranged to cause a simultaneous outhoardturning movement andlowering of the head of the davitarm when the davit-arm is released.

' 11. In a boat launching and stowing apparatus, a davit-arm,track-engaging means on the davit-arm adjacent its central portion andlower end, an outwardly inclined track for the former and a track havingat least a portion thereof inclined inwardly for guiding the latter,which tracks are arranged to cause a simultaneous outboard turningmovement and lowering of the head of the davitarm when the davit-arm isreleased. 7'

In testimony whereof we have signed our names to the specification.

LEONARD ARTHUR DIXON. JAMES BARCLAY PEAT.

